1. Field of the Invention
The present invention relates generally to orthodontic appliances, and specifically to orthodontic appliances reducing friction between an archwire and its archwire holding element by means of repulsive forces due to magnetic or electrical fields.
2. Description of Related Art
Orthodontic appliances are used to correct irregularities or abnormalities in the teeth, particularly problems with misaligned or poorly spaced teeth. The goal is to create the proper bite of the teeth, proper spacing, and proper curvature of the mouth.
Braces attached to the teeth are the most common type of orthodontic appliance. Archwires fit into the braces and correct the position of each tooth by applying a corrective force. The corrective force gradually moves the tooth in the desired direction. The braces include metal, plastic, or ceramic brackets. The archwires fit into slots, tubes, or the like in the brackets. The archwires are metal wires made of nickel-titanium, stainless steel, or other alloys. The slots or tubes in the brackets are generally metal. The archwire is held in the bracket by a rubber band or other means, such as a metal cap attached to the bracket. The bracket is attached to the tooth or teeth by adhesive bonding or by a band. The archwires may slide along the bracket or tube, or the teeth may slide on the archwires. Repeated adjustments by a dentist or orthodontist are required to adjust the archwires and other components so that a force in the desired direction is produced.
A major problem with braces is frictional binding that occurs between the archwire and the bracket, slot, or tube. This frictional binding creates inefficient tooth movement. Frictional binding increases the amount of force that must be applied, since the friction requires force to overcome. If the amount of force applied does not change, frictional binding increases treatment time.
U.S. Pat. Nos. 3,353,271, 4,595,361, 4,671,767, 5,205,736, and 5,334,015 by Blechman disclose various types of orthodontic appliances through which corrective force is applied to teeth by magnets mounted on the teeth. Either attractive or repulsive magnetic force may be used. Blechman does not disclose the use of magnetized archwires, slots, tubes, or brackets. Blechman does not disclose the use of repellent magnetic forces to reduce friction in orthodontic appliances.
U.S. Pat. No. 3,984,915 by Noble discloses the orthodontic movement of teeth in the mouth using magnets directly bonded to the teeth to attract or repel adjacent magnets. Spacing can be corrected and twisted teeth can be torqued in a desired direction.
U.S. Pat. No. 5,607,299 by Nicholson discloses an orthodontic bracket having grooves to reduce friction between the bracket and an archwire.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.